Wow, a whole thread started by me and I didn't even know it!!
Thanks for the compliment, mseds99! For those that missed the other thread, I'll copy my heaviest ever rp experience over here...
The best romance in gaming story I have relates to Nerull. Back when I was running Greyhawk, before Tharizdun ate it (imc), there was an evil pc priest of Nerull (this was in 2e; I'd made individual specialty priests of all the gods around in my campaign at that point) and a good pc ranger who fell in love. After one of those earth-shattering adventures that pcs have where they were rewarded by the gods themselves ("ask for what you will" kind of thing), Egypt (the ranger) asked to bear Carrion's child (Carrion, natch, was the cleric of Nerull).
Well, her request was granted, but Carrion was deeply disturbed. After all, Nerull's creed is to end all life, and creating new life was the worst sin he could conceive of. So the two went on a honeymoon after getting married, far away from any of the rest of the group. One day Carrion walked up to her. "Egypt?"
"Yes?"
"I love you." With that he pulled out his scythe and attacked, trying to slay her. She fought back, not understanding why, until she was on the edge of death. Finally, Carrion threw down his wicked weapon and said flatly, "Kill me."
She was shocked, and in the end, when he told her it was him or her, and made it clear that there was _no way_ to avoid it, she slew him.
It was one of the most shocking bits of play I've ever been involved in. I'd never expected anything like it; I'd not set up any of the story's elements. The players made all the decisions, there was no fudging, and there was real emotional roleplaying going on there. I couldn't believe it; it isn't every day someone sacrifices their own favorite character. He could have renounced his god; he could have slain Egypt; but he chose to die.
Even now, prolly over 10 years later, I can't think of any game I've been in with role playing to match it, or with more of a romantic- and tragically doomed- feeling.
Star-crossed lovers, indeed.
So there you have it, the story that started this thread.